If CSS is the whipped cream, then HTML is the pancake. I like to think of it like the outlet that holds the charger. Because it's a base, there's a limit to what you can do with it in terms of styling. However, without it, you can't do anything at all.
Thankfully, this pancake uses a simple recipe and you can learn how to make it within a few hours. Still, while the basic principals are fairly easy to grasp, every time you learn a new language you sorta have to learn how to incorporate that into the base. So once in an eternity, you might pick up something new haha.
I actually don't think CSS is all too difficult to learn if you've never used a back end language before (HTML doesn't count here). In fact, compared to styling with HTML I would actually call it easier because of how it's organized.
Since I posted that first comment I did end up completing my second year compsci course and learned some java (still a beginner but I can make objects, user controls, and move stuff) but It's been torturous. Java is like math. It is math. Applying it is like calculus. Unfortunately for me, it's also important. But it does do some pretty cool things.
I can see why people who have used Java forever would be annoyed learning CSS. It's like asking a genius mathlete to excel at art class. Just, why? It's a terrible analogy but it encompasses the issue 😅